View Full Version : Is it time for a new injection pump? Dead truck
On the way to work this morning my truck stalled and wouldn't restart. It cranks fine. After towing it home and charging the battery, here is what I know:
1. It cranks fine.
2. There is fuel getting to the IP (after the fuel filter).
3. I opened the rearmost two injector lines on the driver's side. No fuel comes out of there when cranking.
4. No smoke from tailpipes when cranking.
5. The shutoff solonoid clicks when ignition is on and I pull the connected wire.
Is there any more diagnostics I can do? It seems the IP is not pumping fuel but I would hate to misdiagnose this and replace a pump that doesn't need it.
Thanks.
Bob
Are you pulling the red fuel shutoff solenoid wire when you notice the "click", rather than the green HPCA wire?
If the pump still has the original plastic damper ring in the IP's governor, it may have failed, and a piece of it may be blocking the housing pressure regulator valve.
These pumps will not deliver fuel if the return port is restricted.
To check this, disconnect the fuel return line, then remove the complete fitting and housing pressure regulator valve from the top of the IP.
Look inside from the IP side for black chunks. (There is supposed to be a little spring and a glass ball in there.)
Also, you can try to start the engine with the assembly removed. It should either start, or at least full should begin to flow out the top of the pump, if the lift pump and transfer pump are working.
If it starts, shut it down right away, so you aren't pumping diesel fuel over the top of the running engine.
Are you pulling the red fuel shutoff solenoid wire when you notice the "click", rather than the green HPCA wire?
Yep, I'm pulling the red wire, not the green one.
disconnect the fuel return line, then remove the complete fitting and housing pressure regulator valve from the top of the IP.
Okay, I disconnected the fuel return line, removed the brass fitting and the part that the brass fitting was screwed into. That part unscrewed from the top of the pump also and appeared to have a check valve in it. Am I in the right place?
There were no black chunks in there, everything looks clean. When cranking with these fittings off, still no fuel comes out of the pump. I almost removed the cover that those fittings are screwed into... looks like three screws to take it off. But I'm not sure what I'm getting into there or if it's useful.
Any more ideas?
85-m1028
03-11-2006, 15:08
if your engine suddenly goes dead most likely its electrical, I'd check the glow plugs or the controller
if your engine suddenly goes dead most likely its electrical, I'd check the glow plugs or the controller
The truck failed while I was driving down the highway and the engine was at operating temperature. It actually took a few seconds to die. It got weaker until it finally stalled.
I don't think it's related to the glow system since it was running already. I figure either the IP failed or (less likely) something mechanical inside the engine failed which is causing the IP to not be driven. When cranking, there is no fuel getting to the injectors and no fuel coming out the return fitting on the IP, even though fuel is getting to the IP.
Thanks.
Bob
john8662
03-13-2006, 08:34
More things to try.
Remove the oil filler tube from the engine and take note of the gear (or bolts) position on the gear behind the cover. Then crank the engine over, come back and see if the gear/bolt position has moved. This gear that you have access to through the oil filler tube hole is the IP driven gear. So if this is turning, then the timing set, gears, etc. are transferring power to the IP.
The symptoms you describe are as if either the engine ran out of fuel, or the slow seizure of the IP head/internals. Are you getting fuel up to the injection pump? Narrow out all the fuel delivery symptoms, then pull the pump.
Yep, the gear turns when the engine is cranked over. Fuel is at least getting past the filter and into the line leading to the IP. It's pretty unlikely that line is plugged. Looks like next step is to pull the intake manifold, again <sigh>, and pull the pump.
85-m1028
03-14-2006, 09:01
The truck failed while I was driving down the highway and the engine was at operating temperature. It actually took a few seconds to die. It got weaker until it finally stalled.
I don't think it's related to the glow system since it was running already. I figure either the IP failed or (less likely) something mechanical inside the engine failed which is causing the IP to not be driven. When cranking, there is no fuel getting to the injectors and no fuel coming out the return fitting on the IP, even though fuel is getting to the IP.
Thanks.
Bob
ya I was halucinating there for a second I though I read something bout it was running and then wouldnt start, sorry, but I will say that injection pumps dont go dead they gradualy die, did you notice any unusual smoke clouds out the tail pipe, did you open up the top of the pump and check the govener flex ring?
When mine died it seemed to happen rather suddenly, but in reality happened over the course of maybe a week. In hindsight I realized that I'd been having to give it a little more fuel to get the same road speed out of it, till one morning it just lost power over maybe a mile or 2 and I barely limped into a parking lot. The symptoms were the same as yours, I was getting fuel to the pump but nothing to the injectors. Sorry, but I'd say you need a new IP.
No unusual smoke when it died. It just faded off rather quickly. Within 1/2 mile I was on the side of the road.
I pulled the pump tonight. Fuel was definitely getting to it. The pump spins very freely... I think it spins too easily, like something is sheared inside. If I remove those three screws on the top cover and open it up, is there anything special I need to pay attention to when I put it back together? I am curious to see what's in there but don't want to damage anything more.
Looks like it's time for a new IP.
john8662
03-14-2006, 22:06
Sure, pull the top cover off. Just remove the three screws.
This time i'll warn ya, there will be fuel inside to make a mess!
Anyways, the only thing to pay attention to during re-assembly will be fuel shutoff solenoids lever that connects to the internal linkage inside the pump. Once you remove the cover, you'll know what I'm talking about. The only concern when re-assembling the pump will be that the leve be in front of the linkage (so it can push on it). So, I usually slide the cover as far forward (towards the drive portion of the pump) and install the cover (with the solenoid just baraly inside the pump housing. Then slide the cover forward to line up the holes for the re-installation of the cover screws.
Once inside the pump, you'll want to first drain out the Diesel fuel. Then, rotate the the input shaft of the injection pump and see if you can see the shaft down below rotate. Usually a seized head will snap the drive shaft in the pump, and it will break pretty close to the front input shaft. Something to observe.
How much debris or trash is inside? Hopefully it was clean, but since you're in there, you can take a look-see.
The IP driveshaft is "necked down" quite a bit inside the pump, as it will break there without destroying the timing gear train, if the head and rotor seize.
The old IP was very clean inside. However, you may recall from a previous post that the advance wasn't working anyway. The shaft is broken, which kind of explains my no start condition! :-)
I am installing a used IP. There's a Throttle Position Sensor (?) on the passenger side of the IP. What's up with that? I did not think the 6.2, being non-computerized, would have a TPS. What's it for? And, more importantly, how do I set it?
britannic
03-23-2006, 23:06
That TPS is to help control the tranny.
john8662
03-24-2006, 00:37
The TPS is really a "switch" not a sensor, it's used for Both the EGR and the Torque converter lockup in the transmission.
Install the TPS on your injection pump the same way as the old one (aligning holes), or install TPS w/o bolts and rock the TPS wheel until it just baraly touches and a slight spring feel to the stud on the throttle shaft. Then install and tighten the bolts.
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